This invention relates to a new class of cephalosporin compounds. In particular, this invention relates to certain of such cephalosporins having in the 3-position a 5-oxo-6-hydroxy-4,5-dihydro-1,2,4-triazin-3-ylthiomethyl group. The compounds of this invention have excellent broad spectrum gram-positive and gram-negative antibiotic activity.
Broadly, the compounds of this invention have the formula ##STR2## in which R.sub.1 is hydrogen or lower alkyl; R.sub.2 is hydrogen, an alkali metal cation, or a readily removable ester forming group; and R is hydrogen or the group ##STR3## in which R' is hydrogen; C.sub.1 -C.sub.6 alkyl; C.sub.1 -C.sub.3 haloalkyl; C.sub.1 -C.sub.3 cyanoalkyl; C.sub.1 -C.sub.3 azidoalkyl; C.sub.1 -C.sub.3 hydroxylkyl; p-nitrobenzyloxy; 4-amino-4-carboxybutyl; a 4-substituted-amino-4-carboxybutyl ester for the formula ##STR4## in which A is diphenylmethyl, p-nitrobenzyl, benzyl, 2,2,2-trichloroethyl, t-butyl, or p-methoxybenzyl, and A' is C.sub.2 -C.sub.4 alkanoyl, C.sub.2 -C.sub.4 haloalkanoyl, benzoyl, halobenzoyl, 2,4-dinitrophenyl, or phthaloyl; or R' is a group of the formula ##STR5## in which a and a' independently are hydrogen, C.sub.1 -C.sub.4 lower alkyl, C.sub.1 -C.sub.4 lower alkoxy, halogen, hydroxy, or aminomethyl;
Z is O or S; and PA1 m is 0 or 1; PA1 or R' is a group of the formula ##STR6## in which P is 2-thienyl, 3-thienyl, 1-tetrazyl, or a phenyl group of the formula ##STR7## in which a and a' are as defined above; and PA1 Q is hydroxy, formyloxy, acetoxy, carboxy, sulfo, amino, or --NHY in which Y is benzyloxycarbonyl, t-butyloxycarbonyl, ##STR8## in which R'" is hydrogen or C.sub.1 -C.sub.3 alkyl, and V is phenyl, halophenyl, furyl, mono- or di-(C.sub.1 -C.sub.3 alkyl)amino, mono- or diphenylamino, or R'" and V taken together form a heterocycle, R'" being --(CH.sub.2).sub.n -- in which n is 2 or 3, and V being --NR""--, in which R"" is hydrogen, methanesulfonyl, or C.sub.1 -C.sub.3 alkyl; or R' is a group of the formula R"--CH.sub.2 -- in which R" is 2-thienyl; 3-thienyl; 2-furyl; 2-oxazyl; 2-thiazyl; 1-tetrazyl; benzotriazolyl; 1,3,4-thiadiazolyl-2-thio; 1,2,5-thiadiazolyl-3-thio; 1,3,4-oxadiazolyl-2-thia; pyridyl-thia; 1-(4-cyano)-1,2,3-triazolyl; or 1-(3-cyano)-1,2,4-triazolyl.